1. Field of the Invention
The invention relates to energy-saving devices, more specifically, the invention relates to energy-saving controller for three-phase induction motors.
2. Description of the Related Art
The design of induction motors ensures that the motors have high operating power factor and efficiency when they run in the load range from 75% to 100% full load. Thus, high operating power factor and efficiency can be obtained when induction motors run at heavy-load. However, induction motors have low operating power factor and efficiency when they run at light-load or variable-load with low duty ratio.
It is an object of the present invention to improve upon the current design of controllers for induction motors.